In cameras, blur caused by hand shake is often reduced by employing image stabilization. It is attempted to form an image such that each part of an image corresponds to a given narrow beam ahead of the camera even if the camera were slightly shaken. In mechanical image stabilization a stabilized image is achieved by suitably moving the optical unit of the camera or, in case of digital imaging, alternatively or in addition the image sensor.
Modern cameras often implement optical image stabilization by tilting one or more lenses within a barrel of an objective. A typical objective of a single-lens reflex (SLR) camera has easily ten or more lenses and slight tilting of one or more of the lenses may counter handshake by an equivalent of increasing lens aperture by 3-4 exposure value steps without significant distortion in the camera image.